The flash-induced P515 shift in relation to ATPase activity in chloroplasts
| Autor: | Wilma Versluis, Pieter H. van Vliet, Wim J. Vredenberg, Jaap J. J. Ooms |
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| Rok vydání: | 1991 |
| Předmět: |
Photosynthetic reaction centre
Stereochemistry pmf ATPase absorbance change at 518 nm Kinetics Biophysics Photosystem I Chloroplast Biochemistry Chemical kinetics carbonyl cyanide m-chlorophenylhydrazone tentoxin ATP hydrolysis DCCD dicyclohexylcarbodiimide CF0-F1 activation Photosystem ATP synthesis biology ATP synthase Electrochromism Chemistry P515 Laboratorium voor Plantenphysiologisch Onderzoek CCCP protonmotive force DTE dithiothreitol ttx Cell Biology Proton domain biology.protein Laboratory of Plant Physiological Research |
| Zdroj: | Biochimica et biophysica acta-protein structure and molecular enzymology 1056 (1991) Biochimica et biophysica acta-protein structure and molecular enzymology, 1056, 293-300 |
| ISSN: | 0005-2728 0167-4838 |
| DOI: | 10.1016/s0005-2728(05)80061-1 |
| Popis: | The flash-induced P515 signal shows complex kinetics in its rise and decay. The fast rising component, reaction 1/RC, is attributed to the transmembrane charge separation in the reaction centra of Photosystem I and II. The slow component consists of a fast-decaying electrogenic part, reaction 1/Q (due to a Q-cycle) and a slow decaying component, reaction 2. In this work we examined the relation between the onset of flash-induced ATP synthesis, the steady-state ATP synthesis rate and the reaction kinetics of the distinguishable P515 components. The following results have been achieved. (i) The overall P515 decay, if not corrected for reaction 2, is an inadequate measure for the ATPase activation state. (ii) Only the dissipation of the transmembrane electric field, as sensed by reaction 1/RC, is stoichiometrically accelerated by a CF0 proton conductance which, under ATP synthesizing conditions, is added to the actual passive membrane conductance. (iii) ATP hydrolysis does not result in an acceleration of the decay of reaction 1/RC. (iv) The decay of reaction 2 is not altered during activation of the ATPase. |
| Databáze: | OpenAIRE |
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